Downhole brush tool

ABSTRACT

A downhole brush tool ( 10 ) includes a tool body ( 12 ) having a brush supporting portion ( 11, 13 ) on the tool body between upper and lower stops ( 20, 24, 26, 28 ). A split sleeve ( 32, 34 ) has a plurality of throughports ( 30 ) therein, and a plurality of brush elements ( 42 ) including a base member ( 44 ) and a plurality of bristles ( 46 ) extend from the base member. The base member is positioned within a cavity in the brush supporting portion of the tool body, and a stop surface ( 45 ) supported on the split sleeve engages a base member to prevent the brush element from passing radially outward.

FIELD OF THE INVENTION

The present invention relates to a brush tool of the type used to clean debris from the wellbore. More particularly, the present invention relates to a brush tool which reliably positions a plurality of brush elements on a tool body having a relatively large throughbore therein while providing a robust tool.

BACKGROUND OF THE INVENTION

Downhole brush tools have been used for decades to clean the interior of a wellbore and the internal cavities of certain equipment positioned along the wellbore. Prior art downhole brush tools frequently are of the type which are supported on a workstring, with a tool body having a bore in communication with the interior of the workstring and a plurality of brush elements supported on the tool body.

Downhole brush tools are commonly used in conjunction with cleaning fluids which pass through the central bore in a tool body, and accordingly this bore preferably is relatively large to accompany the substantial flow rate commonly pumped through the brush tool, e.g., twenty barrels of cleaning fluid per minute. The brush tool is preferably robust, since the brush tool may be used in a deviated well and the weight of both the tool and a portion of the workstring exert a substantial downward force on the brush bristles. Due to the chemical characteristics of the cleaning fluid, which is often caustic or corrosive, the brush tool preferably keeps the bristles as part of a respective brush element, and provides a substantial force for supporting the brush element, particularly when the tool is rotated and/or reciprocated in a well.

Many prior art brush tools provide slots in the wall of the tool body, with each slot receiving a bar-type support for accommodating the plurality of brush elements. Six or more brush elements may thus be mounted on the bar, and the combination bar and brush elements then secured to the tool body. A close radial spacing between the base of the slot in the tool body and the OD of the bore in the tool body detracts from the overall strength of the tool body, particularly when used in the harsh environment of a cleaning fluid. Another brush tool is disclosed in U.S. Pat. No. 6,523,612.

The disadvantages of the prior art are overcome by the present invention, an improved downhole brush tool is hereinafter disclosed.

SUMMARY OF THE INVENTION

In one embodiment, the downhole brush tool is provided for supporting on a workstring in a wellbore. The tool body includes upper and lower stops each extending radially outward from a brush supporting portion of the tool body. The brush supporting portion of the tool body includes at least one cavity therein extending radially inward of a generally cylindrical exterior surface of the brush supporting portion, and a split sleeve having a plurality of throughports therein is supported on the brush supporting portion. The plurality of brush elements each include a base member and a plurality of bristles extending from the base member. The base member of each of the plurality of brush elements is positioned at least partially within the cavity in the brush supporting portion of the tool body, while the plurality of bristles extend radially outward from a respective throughport in the split sleeve. A stop supported on the split sleeve engages the base member to prevent the brush element from passing radially outward through a respective throughport in the split sleeve.

These and further features and advantages of the present invention will become apparent from the following detailed description, wherein reference is made to the figures in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a brush tool according to the present invention.

FIG. 2 is a top view of a split sleeve for positioning on a brush supporting portion of the tool body.

FIG. 3 is a side view of a suitable brush element.

FIG. 4 is a cross-sectional view of the tool shown in FIG. 1, showing radially opposing brush elements supported on the tool body and extending through the split sleeve.

FIG. 5 is a cross-sectional view of another embodiment of a brush tool.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 illustrates a downhole brush tool 10 for supporting on a workstring (not shown) such that the central bore 14 in the tool body 12 is in fluid communication with the interior of the workstring. The workstring extends to the surface, and allows the tool to be reciprocated and/or rotated in the well. Brushes may be provided both above stop 26 and below stop 28, each extending outward from the generally cylindrical tool body surface 16, although the brushes and sleeve halves have been removed from the lower part of the tool.

Annular upper stop 20 and annular lower stop 24, as well as intermediate stops 26 and 28, provide stops for limiting axial movement of the brushes, as explained subsequently. A plurality of cavities 50 in the tool body are provided each for receiving a base portion of a brush element. Brush supporting portions 13 on the tool body may each include one or more cavities 50 therein extending radially inward of a generally cylindrical exterior surface of the brush supporting portion. Brush base member 44 as shown in FIG. 3 is preferably a sleeve shaped member with a bottom or base plate for contacting a lower end of the plurality of bristles. A split sleeve formed by sleeve halves 32, 34 as shown on FIG. 2 are supported on the brush supporting portion of the tool body, and have a plurality of throughports 30 therein. These ports may be arranged in a manner such that the plurality brushes extend radially from the tool body with the brush elements arranged in a vertically staggered and circumferentially staggered configuration. A pin end 18 of the tool body mates with a box end of a tubular or tool below 18.

FIG. 3 illustrates one of the brushes 42 which includes a base member 44 and a plurality of bristles 46 fixedly secured to and extending from the base member. The plurality of bristles may be secured to the base member by a crimping operation performed on the base member 44. Alternatively, the base member and at least a lower portion of the bristles within the cavity in the base member may be heated and bonded together, such that the bristles are effectively welded to the base member.

The split sleeves 32, 34 as shown in FIG. 2 include conventional fasteners 36 for maintain the ends 38, 40 of the sleeve halves together while the brush elements are mounted on the tool body, but these fasteners may be released so that the split sleeves may be removed from the tool body and the brush elements replaced.

FIG. 4 is a cross-section of the tool shown in FIG. 1, illustrating a substantial diameter throughbore 14 in the tool body 12 and the split sleeves 32, 34 secured about the tool body. The split sleeves are thus restricted by the stops 20, 26, 28 and 24 from substantial axial movement along the tool body. In FIG. 4, the base element 44 of each brush element is positioned substantially entirely within the tool body, while the bristles 46 extend through a respective aperture 30 in the split sleeve and thus extend radially outward from a tool body. The brush element is held in place by a radially outward end of the split sleeve 44 engaging the inner surface 45 of a split ring circumferentially about a respective throughport 30, so that the base member and the bristles secured thereto cannot pass radially outward through the tool body on the split sleeve. Each brush element includes a central brush element axis, and each brush element axis is substantially mounted perpendicular to an outer generally cylindrical surface of the split sleeve.

FIG. 5 is a cross-sectional view of another embodiment of a brush tool, so FIG. 5 is an alternative to the FIG. 4 embodiment. The tool body 12 has a central bore 14 which, in this case, is significantly larger than the bore 14 in the FIG. 4 embodiment for passing substantial quantities of fluid through the tool. The tool includes a pair of split sleeves 32, 34 as discussed above, and the brush 42 has an oversized diameter base 52 and radially extending bristles 46. The brushes thus extend through pockets or holes in the split sleeves 32, 34. The corner 50 of the large diameter base tapering toward the bristles is positioned partly within the sleeve, thereby positioning the base of the brush radially outward as far as practical to maintain tool strength while allowing for the large diameter throughbore 14.

In a preferred embodiment, the tool body is provided with short generally cylindrical shaped pockets each for receiving a base of the appropriate brush element. In alternate embodiments, the individual pocket for each brush base may not be provided, and instead a slot may be provided for receiving a plurality of brush bases, with the brushes each extending through the appropriate hole in the sleeve for performing a cleaning function.

The design of the brush tool as disclosed herein also has the benefit of providing a substantial structural support to the brush elements mounted on the tool body. The bristles are not only fixedly secured to the base member, but a lower portion of the bristles radially outward of the base member engage the sidewalls of throughport 30 in the split sleeve, thereby providing additional support for the bristles and preventing the bristles from breaking free from the base member. In alternate embodiments, a portion of the base member could be provided in the split sleeve and another portion positioned in the tool body, so that the stop surface on the sleeve is spaced between the radially outer surface and the radially inner surface of the split sleeve.

Although specific embodiments of the invention have been described herein in some detail, this has been done solely for the purposes of explaining the various aspects of the invention, and is not intended to limit the scope of the invention as defined in the claims which follow. Those skilled in the art will understand that the embodiment shown and described is exemplary, and various other substitutions, alterations and modifications, including but not limited to those design alternatives specifically discussed herein, may be made in the practice of the invention without departing from its scope. 

1. A downhole brush tool for supporting on a workstring to clean a wellbore, comprising: a tool body having a central throughbore in fluid communication with an interior of the workstring, and having axially spaced upper and lower stops each extending radially outward from a brush supporting portion of the tool body spaced axially between the upper and lower stops; the brush supporting portion of the tool body including a plurality of cavities therein extending radially inward of a generally cylindrical exterior surface of the brush supporting portion; a split sleeve supported on the brush supporting portion of the tool body and having a plurality of throughports therein; a plurality of brush elements each including a base member and a plurality of bristles fixedly secured to and extending from the base member; the base member of each of the plurality of brush elements positioned at least partially within the cavity in the brush supporting portion of the tool body while the plurality of bristles extend radially outward from a respective throughport in the split sleeve; and a stop supported on the split sleeve for engaging a respective base member to prohibit a brush element from passing radially outward through a respective throughport in the split sleeve.
 2. The downhole brush tool as defined in claim 1, wherein each brush element includes a central brush element axis, and each brush element axis is substantially perpendicular to an outer generally cylindrical surface of the split sleeve.
 3. The downhole brush tool as defined in claim 1, wherein the split sleeve comprises first and second C-shaped sleeve portions, and ends of the C-shaped portions are secured together by fasteners.
 4. The downhole brush tool as defined in claim 1, wherein substantially the entirety of each brush element base member is positioned within the tool body.
 5. The downhole brush tool as defined in claim 1, wherein the base member has a generally sleeve-shaped body receiving a lower portion of the plurality of bristles therein.
 6. The downhole brush tool as defined in claim 1, wherein the plurality of brush elements are arranged circumferentially and axially along the tool body, and a corresponding cylindrical shaped cavity in the tool body receives at least a portion of a respective brush element base member therein.
 7. The downhole brush tool as defined in claim 1, wherein the base member diameter is larger than a diameter of a corresponding throughport in the split sleeve.
 8. The downhole brush tool as defined in claim 1, wherein the base member engages the stop on a radially interior surface of the split sleeve.
 9. A downhole brush tool for supporting on a workstring to clean a wellbore, comprising: a tool body having a central throughbore in fluid communication with an interior of the workstring, and having axially spaced upper and lower stops each extending radially outward from a brush supporting portion of the tool body spaced axially between the upper and lower stops; the brush supporting portion of the tool body including a plurality of cavities therein each extending radially inward of a generally cylindrical exterior surface of the brush supporting portion; a split sleeve supported on the brush supporting portion of the tool body and having a plurality of throughports therein, a split sleeve comprising first and second C-shaped sleeve portions; a plurality of brush elements each including a base member and a plurality of bristles fixedly secured to and extending from the base member; the base member of each of the plurality of brush elements positioned at least partially within a respective cavity in the brush supporting portion of the tool body while the respective plurality of bristles extend radially outward from a respective throughport in the split sleeve; and a stop supported on the split sleeve for engaging the base member to prohibit a brush element from passing radially outward through a respective throughport in the split sleeve.
 10. The downhole brush tool as defined in claim 9, wherein each brush element includes a central brush element axis, and each brush element axis is substantially perpendicular to an outer generally cylindrical surface of the split sleeve.
 11. The downhole brush tool as defined in claim 9, wherein substantially the entirety of each brush element base member is positioned within the tool body.
 12. The downhole brush tool as defined in claim 9, wherein the base member diameter is larger than a diameter of a corresponding throughport in the split sleeve.
 13. The downhole brush tool as defined in claim 9, wherein the plurality of brush elements are arranged circumferentially and axially along the tool body.
 14. The downhole brush tool as defined in claim 9, wherein the base member engages the stop on a radially interior surface of the split sleeve.
 15. A downhole brush tool for supporting on a workstring to clean a wellbore, comprising: a tool body having a central throughbore in fluid communication with an interior of the workstring, and having axially spaced upper and lower stops each extending radially outward from a brush supporting portion of the tool body spaced axially between the upper and lower stops; the brush supporting portion of the tool body including a plurality of cavities therein each extending radially inward of a generally cylindrical exterior surface of the brush supporting portion; a split sleeve supported on the brush supporting portion of the tool body and having a plurality of throughports therein; a plurality of brush elements each including a base member and a plurality of bristles fixedly secured to and extending from the base member; the base member of each of the plurality of brush elements positioned at least partially within a respective cavity in the brush supporting portion of the tool body while the respective plurality of bristles extend radially outward from a respective throughport in the split sleeve; and a radially interior surface of the split sleeve forming a stop or engaging the base member to fit the brush member from passing radially outward through a respective throughport in a split sleeve.
 16. The downhole brush tool as defined in claim 15, wherein the split sleeve comprises first and second C-shaped sleeve portions, and ends of the C-shaped portions are secured together by fasteners.
 17. The downhole brush tool as defined in claim 15, wherein the plurality of brush elements are arranged circumferentially and axially along the tool body, and each brush element includes a central brush element axis, and each brush element axis is substantially perpendicular to an outer generally cylindrical surface of the split sleeve.
 18. The downhole brush tool as defined in claim 15, wherein the base member diameter is larger than a diameter of a corresponding throughport in the split sleeve.
 19. The downhole brush tool as defined in claim 15, wherein substantially the entirety of each brush element base member is positioned within the tool body.
 20. The downhole brush tool as defined in claim 15, wherein the base member engages the stop on a radially interior surface of the split sleeve. 